Long ago at work there was temp who was liked by many pf the employees. I'd overhear her attacking her predecessor whom she had never met who had done the job she was doing temporarily. She did not know that person was my best friend at the time. She was also very rude to me so maybe she did know that. At any rate "they" were considering hiring her for a permanent position. I had a closed-door meeting with the Vice President in charge of that department for whom my best friend had worked for years. He was a huge fan of hers. She was very smart and creative and an asset to the company. When I told him what the temp said, how she treated me and what she was really like he did not hire her. She never knew why and neither did those who wanted her aboard as far as I know. You never know who might have power over you so it's best to be civil to everyone. As far as I know no one but the vice president and I ever knew the truth.
